Breathable absorbent articles and composites comprising a vapor permeable, liquid barrier layer

ABSTRACT

The present invention relates to absorbent articles and composites that provide improved protection and comfort by use of a vapor permeable, liquid barrier layer. In particular, this layer results from deposition of barrier coating on one or more regions of the barrier layer such that select regions of the overall article exhibit a barrier to liquid while the article in general is still deemed breathable.

FIELD OF INVENTION

The present invention relates to absorbent articles and composites thateach include a barrier layer which helps to provide 1) improvedprotection against wetness strikethrough that typically results fromimpact or sustained pressure, 2) improved dampness management character,and 3) high convective vapor flow through for skin health and comfortbenefits.

BACKGROUND OF THE INVENTION

Many known absorbent articles such as diapers, incontinence articles,feminine hygiene products, and training pants, typically compriseabsorbent core materials located between a liquid pervious bodysideliner or topsheet and a vapor permeable, liquid impermeable backsheet.The bodyside liner allows bodily liquids to flow through easily towardsthe absorbent core. The absorbent core takes up the liquids quickly.Thus, no excessive pooling of liquids occurs on the body-facing surfaceof the absorbent article. The outer cover is typically liquidimpermeable such that there is no leakage from the absorbent article.Since, however, the disposable absorbent article may be worn for hoursafter coming in contact with body exudates and perspiration from thewearer's body, liquid vapors escaping from the absorbent core often getentrapped in the space between the absorbent article and the wearer'sskin, resulting in an increased relative humidity in the occluded area.As is known in the art, the increased relative humidity leads todiscomfort and overhydrated skin that is prone to skin health problems,especially rashes and other contact dermatitis.

Such backsheets are well suited to prevent the leakage of bodily fluids(such as urine, menses or fecal matter) from the absorbent material tothe outer garment of a wearer. Unfortunately, the use of such animpermeable backsheet can result in a high degree of humidity in theabsorbent article when the absorbent article is in use such thatrelatively elevated skin hydration levels may result.

Attempts at remedying this problem have included utilizing microporousor monolithic films as backsheet materials which then allow air andwater vapor diffusion. Others have tried incorporating high permeabilityzones within the absorbent core, such as by aperturing the absorbentcore or by creating portions in the core containing substantially lesshigh absorbency materials than in other portions of the core. Absorbentarticles relying on these technologies have still tended to exhibitsignificantly increased relative humidity between the skin of the wearerand the article when the article is loaded with liquids.

One phenomenon of particular interest that affects a loaded or wetabsorbent article is any pressure or impact force due to the wearer'smotion, such as sitting, walking, bending, and falling. Known absorbentarticles still tend to fail to hold liquids when they are loaded totheir absorbent capacity especially when the loaded absorbent article isunder pressure or impact due to a wearer's motion.

It has been observed by the Applicants that convective vapor flow ismuch more effective than diffusive vapor flow when there is a dampabsorbent article core present. Consequently, there is a need forabsorbent articles which deliver a combination of benefits to thewearer. These benefits should include an improved liquid impactcapability, breathability (i.e., air vapor flow via convection), watervapor transmission (i.e., through diffusion) and resistance to leakageunder impact or sustained pressure.

SUMMARY OF THE INVENTION

The present invention relates to a disposable absorbent articlecomprising:

-   -   a. a liquid permeable topsheet;    -   b. a liquid impervious outer cover;    -   c. an absorbent core disposed between said topsheet and outer        cover, wherein said core comprises a first and second region;        and    -   d. a barrier layer disposed either between said topsheet and        core or between said core and outer cover, wherein said barrier        layer comprises:        -   1) a first region;        -   2) a second region disposed adjacent said first region of            said barrier layer; and        -   3) a barrier coating disposed onto one or more surfaces of            said first region of said barrier layer; wherein said            barrier coating inhibits the flow of a liquid in the first            region of said barrier layer as compared to the flow of the            liquid in the second region of said barrier layer; and    -   wherein said first region of said barrier layer exhibits a water        vapor transmission rate (WVTR) of from about 100 to about 50,000        gsm/day and a convective air permeability of at least about 0.01        cfm.

In another embodiment, the present invention relates to a disposablecomposite that comprises:

-   -   a. a first region;    -   b. a second region;    -   c. a barrier coating disposed onto one or more surfaces of said        first region of said barrier layer; wherein said barrier coating        inhibits the flow of a liquid in the first region of said        barrier layer as compared to the flow of the liquid in the        second region of said barrier layer; and    -   wherein said first region of said barrier layer exhibits a water        vapor transmission rate (WVTR) of from about 100 to about 50000        gsm/day and a convective air permeability of at least about 0.01        cfm.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a partially broken top plan view of an absorbent article ofthe present invention which includes a barrier layer.

FIG. 2 is a top plan view of a composite of the present invention.

FIG. 3 is a top plan view of a striped barrier coated composite of thepresent invention.

FIG. 4 is a front view of the dynamic liquid impact tester that is usedrelative to the present invention.

DETAILED DESCRIPTION OF THE INVENTION Definitions

As used herein, the term “absorbent articles” refers to devices thatabsorb and contain body exudates, and, more specifically, refers todevices that are placed against or in proximity to the body of thewearer to absorb and contain the various exudates discharged from thebody. Absorbent articles may include diapers, training pants, adultincontinence undergarments, feminine hygiene products, breast pads, caremats, bibs, wound dressing products, and the like. As used herein, theterm “body fluids” or “body exudates” includes, but is not limited to,urine, blood, vaginal discharges, breast milk, sweat and fecal matter.

As used herein, the term “absorbent core” refers to the component of theabsorbent article that is primarily responsible for fluid handlingproperties of the article, including acquiring, transporting,distributing and storing body fluids. As such, the absorbent coretypically does not include the topsheet, backsheet or outer cover of theabsorbent article.

As used herein, the term “bonded” refers to different materials beingattached (cohesively or adhesively) in at least a portion thereof. Theattached portions may be random or may have a pattern such as stripes,spirals, dots, and the like. The attached portions may be located at theperipheries, throughout the surface area, or both. Suitable attachmentmeans known in the art may be used, including but not limited toadhesives, heat, pressure, crimping, ultrasonic, chemical (via hydrogenbonds or other cohesive forces), mechanical (e.g., fasteners,entanglements), hydraulic, vacuum and combinations thereof.

As used herein, the term “composite structure” refers to a multi-regionstructure wherein the materials comprising the regions may beoperatively associated or bonded. The regions may even be in intimatecontact such that the composite has a unitary structure. Further, theregions may be positioned in a layered (face-to-face) arrangement, or aside-by-side arrangement.

As used herein, the term “disposable” is used in its ordinary sense tomean an article that is disposed or discarded after a limited number ofusage events over varying lengths of time, preferably less than about 20events, more preferably less than about 10 events, even more preferablyless than about 5 events, and most preferably less than about 2 events.

As used herein, the term “joined” encompasses configurations wherein anelement is directly secured to the other element by affixing the elementdirectly to the other element, and configurations wherein the element isindirectly secured to the other element by affixing the element tointermediate member(s), which in turn are affixed to the other element.

The term “macroporous” refers to materials having pores too large toeffect capillary transport of fluid, generally having pores greater thanabout 0.5 mm in diameter and, more specifically, having pores greaterthan about 1.0 mm in diameter.

As used herein, the terms “meltblown” and “meltblown web” refer to a webhaving fibers formed by extruding a molten thermoplastic materialthrough a plurality of fine, usually circular, die capillaries as moltenthreads or filaments into converging high velocity heated gas/airstreams which attenuate the molten filaments to reduce their diameter.The reduction in fiber diameter is substantially greater then thereduction of fiber diameter in the spunbonding process, resulting inmicrofibers having average fiber diameter larger than 0.2 microns andtypically in the range of 0.6 to 10 microns. Thereafter, the meltblownfibers are carried by the high velocity gas stream and are deposited ona collecting surface to form a web of randomly disbursed fibers. Variousmelt blown processes are known in the art.

As used herein, the term “microporous” refers to materials which arecapable of transporting fluids through relatively small pores thatpossess tortuous paths.

As used herein, the terms “nonwoven” and “nonwoven web” refers to a webthat has a structure of individual fibers which are interlaid forming amatrix, but not in an identifiable repeating manner. Nonwoven webs maybe formed by a variety of processes known to those skilled in the art,for example, meltblowing, spunbonding, wet-laying, air-laying, andvarious bonding-carding processes.

As used herein, the term “operatively associated” refers to a structurecomprising different materials positioned at least in partial contactwith each other in use. The materials are physically separable and eachexhibits properties that can be measured individually. The materials maybe arranged in a face-to-face relationship in the z-dimension, or in aside-by-side relationship in the xy-dimension.

As used herein, the term “pulp” or “cellulosic fibers” include thosenatural fiber derived from trees or vegetations (e.g., hardwood fibers,softwood fibers, hemp, cotton, flax, esparto grass, milkweed, straw,bagasse and the like), their processed/regenerated fibers (e.g., Rayon®)or chemically derivatized fibers (e.g., cellulose esters), andcombinations thereof. Suitable hardwood fibers include eucalyptusfibers. Suitable hardwood fibers may be prepared by kraft or otherchemical pulping methods. Suitable softwood fibers include southernsoftwood (SS) fibers and northern softwood (NS) fibers. Softwood fibersfor use herein can be chemically (e.g., without limitation, kraft pulp)or mechanically pulped (e.g., without limitation, chemithermalmechanical pulp (CTMP) and thermal mechanical pulp (TMP)).

As used herein, the term “region” refers to a zone or an area comprisinga material being physically, chemically, or visually distinguishablefrom surrounding or adjoining materials. Various regions of materialsmay include transitional regions in between. The regions may bepositioned in the z-dimension or in the xy-dimension. As used herein,the term “z-dimension” refers to the dimension orthogonal to the lengthand width of the structure or article. The z-dimension usuallycorresponds to the thickness of the structure or article. As usedherein, the term “xy-dimension” refers to the plane orthogonal to thethickness of the member, core or article when the member, core orarticle is in a flat-out state. The xy-dimension usually corresponds tothe length and width, respectively, of the structure or article in aflat-out state.

As used herein, the terms “spunbond” and “spunbonded web” refers to aweb having fibers formed by extruding a molten thermoplastic material asfilaments from a plurality of fine capillaries of a spinnerette having acircular or other configuration, then rapidly reducing the diameter ofthe extruded filaments by fluid drawing or other well known spunbondingmechanisms. Spunbond fibers are quenched and generally not tacky whenthey are deposited onto a collecting surface. Spunbond fibers aregenerally continuous and often have average between about 10 to about 30microns.

As used herein, the term “unitary structure” refers to a structurecomprising materials having different characteristics joined together toform an integral entity such that the materials are substantiallyinseparable physically, and the unitary structure exhibits propertiesresulting from the combination of the materials therein. The materialsmay be arranged in a face-to-face relationship in the z-dimension, or ina side-by-side relationship in the xy-dimension.

The following detailed description is directed toward absorbentarticles. It is, however, likely that the disclosed articles could bemodified such that the overall concept discussed herein could likewisebe applied to use in other hygiene or health care products, such asbandages, dressings, wipes, bibs, surgical drapes, surgical gowns, andthe like.

Absorbent Article Components

FIG. 1 is a partially broken top plan view of a particular absorbentarticle of the present invention. This article is a diaper 20 containingthe barrier layer 10 of the present invention. The diaper 20 is in aflat-out state with portions of the structure cut away to more clearlyshow the construction of the diaper 20. The garment-facing surface ofthe diaper 20 is oriented away from the viewer.

As shown in FIG. 1, the diaper 20 comprises a liquid pervious topsheet24; an absorbent core 28, which is positioned between at least a portionof the topsheet 24 and the outer cover 22; a barrier layer 10 positionedbetween the absorbent core 28 and the outer cover 22; side panels 30;elasticized leg cuffs 32; elastic waist features 34; and a fasteningsystem 40.

Diaper 20 is shown in FIG. 1 to have a front waist region 36, a rearwaist region 38 opposed to the front waist region 36 and a crotch region37 located between the front and the rear waist regions. The peripheriesof the diaper 20 are defined by the outer edges of the diaper 20 inwhich the longitudinal edges 50 run generally parallel to thelongitudinal centerline 100 of the diaper 20 and end edges 52 runbetween the longitudinal edges 50 generally parallel to the lateralcenterline 110 of the diaper 20.

The main body of the diaper 20 comprises at least the absorbent core 28,and the topsheet 24. An outer cover 22 forms the chassis, onto whichother components of the diaper 20 are added to form the unitarystructure of the diaper.

FIG. 1 shows an embodiment of the diaper 20 in which the topsheet 24 haslength and width dimensions generally no smaller than those of theabsorbent core 28 and the barrier layer 10. The topsheet 24 may extendto the peripheries of the diaper 20. In another embodiment, the barrierlayer 10 may extend beyond the edges of the absorbent core 28 to theperipheries or edges of the diaper 20.

While the components of the diaper 20 may be assembled in various wellknown configurations, preferred diaper configurations are describedgenerally in U.S. Pat. Nos. 3,860,003, 5,151,092, 5,221,274, 5,554,145,5,569,234, 5,580,411, and 6,004,306.

In alternative embodiments, the article may be preformed by themanufacturer to create a pant. The term “pant”, as used herein, refersto disposable garments having a waist opening and leg openings designedfor infant or adult wearers. A pant may be placed in position on thewearer by inserting the wearer's legs into the leg openings and slidingthe pant into position about the wearer's lower torso. A pant may bepreformed by any suitable technique including, but not limited to,joining together portions of the article using refastenable and/ornon-refastenable bonds (e.g., seam, weld, adhesive, cohesive bond,fastener, etc.). While the term “pant” is used herein, pants are alsocommonly referred to as “closed diapers”, “prefastened diapers”,“pull-on diapers”, “training pants” and “diaper-pants”. Suitable pantsare disclosed in U.S. Pat. Nos. 5,246,433; 5,569,234, 6,120,487,6,120,489, 4,940,464, 5,092,861, 5,897,545, 5,957,908, and U.S. PatentPublication 2003/0233082A1.

Topsheet

The topsheet is compliant, soft feeling, and non-irritating to thewearer's skin. The topsheet material can also be elastically stretchablein one or two directions. Further, the topsheet is fluid pervious,permitting fluids (e.g., urine, menses, other bodily fluids) to readilypenetrate through its thickness. A suitable topsheet can be manufacturedfrom a wide range of materials such as woven and nonwoven materials;apertured or hydroformed thermoplastic films; porous foams; reticulatedfoams; reticulated thermoplastic films; and thermoplastic scrims.Suitable woven and nonwoven materials may comprise of natural fiberssuch as wood or cotton fibers; synthetic fibers such as polyester,polypropylene, or polyethylene fibers; or combinations thereof. If thetopsheet includes fibers, the fibers may be spunbond, carded, wet-laid,meltblown, hydroentangled, or otherwise processed as is known in theart. One suitable topsheet comprising a web of staple-lengthpolypropylene fibers is manufactured by BBA Nonwovens of Old Hickory,Tenn. and us available under the designation P-8.

Preferred topsheet for use in the present invention are selected fromhigh loft nonwoven topsheets and apertured film topsheet. Apertured filmtopsheet typically are pervious to bodily exudates, yet non-absorbent,and have a reduced tendency to allow fluids to pass back through andrewet the wearer's skin. Suitable apertured films include thosedescribed in U.S. Pat. No. 5,628,097, U.S. Pat. No. 5,916,661, WO00/69382 A2, U.S. Pat. No. 6,545,197, and U.S. Pat. No. 6,107,539.

Further, suitable topsheet materials for depositing solid excretionsthereon may include nonwovens having apertures, which are at least inthe portions that are aligned with the feces deposition region of thearticle. Suitable apertured nonwovens are described in more detail inU.S. Pat. Nos. 6,414,215, 5,342,338, and 5,941,864 and U.S. PatentPublication 2002/017376. In another embodiment of feces handlingarticles, such topsheets can be combined with feces handling members,e.g., underlying such topsheets, and which are further described in theabovementioned patent documents.

Suitable formed film topsheets are described in U.S. Pat. Nos.3,929,135, 4,324,246, 4,342,314, 4,463,045, 5,006,394. Other suitabletopsheets may be made in accordance with U.S. Pat. Nos. 4,609,518 and4,629,643. Such formed films are available as “DRI-WEAVE” and “CLIFF-T”and are available from Tredegar Corporation, based in Richmond, Va.

Preferably, at least a portion of the topsheet 24 is made of ahydrophobic material or is treated to be hydrophobic in order to isolatethe wearer's skin from liquids contained in the absorbent core 28. Ifthe topsheet 24 is made of a hydrophobic material, preferably at least aportion of the upper surface of the topsheet 24 is treated to behydrophilic so that liquids will transfer through the topsheet morerapidly. The topsheet 24 can be rendered hydrophilic by treating it witha surfactant or by incorporating a surfactant into the topsheet.Suitable methods for treating the topsheet 24 with a surfactant includespraying the topsheet 24 material with the surfactant and/or immersingthe material into the surfactant. A more detailed discussion of such atreatment and hydrophilicity is contained in U.S. Pat. Nos. 4,988,344,4,988,345, and 4950254. A more detailed discussion of some suitablemethods for incorporating a surfactant in the topsheet 24 can be foundin U.S. Statutory Invention Registration No. H1670 published on Jul. 1,1997 in the names of Aziz et al. Alternatively, the topsheet 24 mayinclude an apertured web or film which is hydrophobic. This may beaccomplished by eliminating the hydrophilizing treatment step from theproduction process and/or applying a hydrophobic treatment to thetopsheet 24, such as a polytetraflouroethylene compound like SCOTCHGUARDor a hydrophobic lotion composition, as described below. In suchembodiments, it is preferred that the apertures be large enough to allowthe penetration of aqueous fluids like urine without significantresistance.

Any portion of the topsheet 24 may be coated with a lotion as is knownin the art. Examples of suitable lotions include those described in U.S.Pat. Nos. 5,607,760, 5,609,587, 5,635,191, 5,643,588, and 5,968,025. Thelotion may function alone or in combination with another agent as thehydrophobizing treatment described above. The topsheet may also includeor be treated with antibacterial agents, some examples of which aredisclosed in PCT Publication No. WO 95/24173. Further, the topsheet, theouter cover or any portion of the topsheet or outer cover may beembossed and/or matte finished to provide a more cloth like appearance.

The topsheet may comprise one or more apertures to ease penetration ofexudates therethrough, such as urine and/or feces (solid, semi-solid, orliquid). The size of at least the primary aperture is important inachieving the desired waste encapsulation performance. If the primaryaperture is too small, the waste may not pass through the aperture,either due to poor alignment of the waste source and the aperturelocation or due to fecal masses having a diameter greater than theaperture. If the aperture is too large, the area of skin that may becontaminated by “rewet” (from the article) is increased. Typically, theaperture should have an area of between about 10 cm² and about 50 cm².The aperture preferably has an area of between about 15 cm² and 35 cm².

Further, the topsheet may be fully or partially elasticated or may beforeshortened so as to provide a void space between the topsheet and thecore. Exemplary structures including elasticized or foreshortenedtopsheets are described in more detail in U.S. Pat. Nos. 4,892,536,4,990,147, 5037416; and 5269775.

Absorbent Core

The absorbent core may take on any size or shape that is compatible withthe diaper. One preferred embodiment of the diaper has an asymmetric,modified T-shaped absorbent core having ears in the first waist regionbut a generally rectangular shape in the second waist region. Exemplaryabsorbent structures for use as the absorbent core of the presentinvention that have achieved wide acceptance and commercial success aredescribed in U.S. Pat. Nos. 4,610,678, 4,673,402, 4,888,231, 4,834,735,5,137,537, 5,147,345, 5,342,338, 5,260,345, 5,387,207, 5,234,423, and5,625,222.

The absorbent core typically comprises absorbent materials includingabsorbent gelling materials, which are usually referred to as“hydrogels”, “superabsorbent”, “hydrocolloid” materials. Absorbentgelling materials are those materials that, upon contact with aqueousfluids, such as bodily fluids, imbibes such fluids and form hydrogels.These absorbent gelling materials are typically capable of absorbinglarge quantities of aqueous bodily fluids, and further capable ofretaining such absorbed fluids under moderate pressures. These absorbentgelling materials are typically in the form of discrete, nonfibrousparticles. Other forms, such as fibers, foams, sheets, strips, or othermacrostructures, are also suitable for use herein. Suitable absorbentgelling materials in the form of open cell foams may include thosedisclosed in U.S. Pat. Nos. 3,563,243, 4,554,297, 4,740,520, and5260345.

The absorbent gelling materials suitable for use herein may comprise asubstantially water-insoluble, slightly crosslinked, partiallyneutralized, polymeric gelling material. This material forms a hydrogelupon contact with water. Suitable absorbent gelling materials includethose disclosed in U.S. Pat. Nos. 4,654,039, 5,562,646, 5,599,335, and5,669,894.

Such absorbent gelling materials can be arranged in a homogeneous mixingwith fluff pulp and/or synthetic fibers (as described herein), or can belayered between suitably open and permeable layers of porous materials,such as tissues, especially if these are air-laid, or nonwovenmaterials.

Particularly suitable materials are superabsorbent materials of U.S.Pat. No. 5,599,335, when arranged in a homogeneous blend withconventional fluff pulp, at a concentration of about 50% superabsorbent,preferably about 80% and even more preferably more than about 90%concentration based on the weight of the superabsorbent/fluff mixture.Suitable mixtures can further exhibit densities of between about 0.1g/cm³ and about 0.3 cm³, preferably between about 0.15 cm³ and about 0.2cm³.

In particular embodiments, such mixtures can comprise means whichenhance the integrity of the mixture, especially in the dry state. Thus,low amounts of adhesive may be added to the mixture, or other binders,such as thermobondable synthetic fibers.

In addition to the liquid storage elements in the core, the core maycomprise other liquid handling members, such as for enhancing fluidacquisition, or distribution.

Suitable carrier materials for inclusion into the core include cellulosefibers, in the form of fluff, tissues or paper. Modified cellulosefibers (e.g., stiffened, chemically treated, crosslinked) may also beused. Synthetic fibers may also be used. Suitable synthetic fibers maybe made of cellulose acetate, polyvinyl fluoride, polyvinylidenechloride, acrylics (such as Orlon®), polyvinyl acetate, non-solublepolyvinyl alcohol, polyethylene, polypropylene, polyamides (such asNylon®), polyesters, bi- or tri-component fibers thereof, and mixturesof these materials. Preferably, the fiber surfaces are hydrophilic orare treated to be hydrophilic.

Typically, the core comprises from about 15 to about 100 wt % of theabsorbent gelling material dispersed in a carrier material. Preferably,the core comprises from about 30 to about 95 wt %, more preferably fromabout 60 to about 90 wt % of the absorbent gelling material. The carriermaterial typically comprises from about 0 to about 85 wt %, preferablyfrom about 5 to about 70 wt %, and more preferably from about 10 toabout 40 wt % of the storage layer.

In certain embodiments of the present invention, the absorbent articlemay also include a sublayer disposed between the topsheet and the outercover. The sublayer may be any material or structure capable ofaccepting, storing or immobilizing bodily exudates. Thus, the sublayermay include a single material or a number of materials operativelyassociated with each other. Further, the sublayer may be integral withanother element of the absorbent article or may be one or more separateelements joined directly or indirectly with one or more elements of thearticle. Further, the sublayer may include a structure that is separatefrom the core or may include or be part of at least a portion of thecore.

Suitable materials for use as the sublayer may include large cell openfoams, macro-porous compression resistant nonwoven highlofts, large sizeparticulate forms of open and closed cell foams (macro and/ormicroporous), highloft nonwovens, polyolefin, polystyrene, polyurethanefoams or particles, structures comprising a multiplicity of verticallyoriented looped strands of fibers, absorbent core structures describedabove having punched holes or depressions, and the like. One embodimentof a sublayer includes a mechanical fastening loop landing element,having an uncompressed thickness of about 1.5 millimeters available asXPL-7124 from the 3M Corporation of Minneapolis, Minn. Anotherembodiment includes a 6 denier, crimped and resin-bonded nonwovenhighloft having a basis weight of 110 grams per square meter and anuncompressed thickness of 7.9 millimeters which is available from theGlit Company of Wrens, Ga. Other suitable absorbent and nonabsorbentsublayers are described in U.S. Pat. Nos. 6,680,422 and 5,941,864.Further, the sublayer, or any portion thereof, may include or be coatedwith a lotion or other known substances to add, enhance or change theperformance or other characteristics of the element.

Outer Cover

The term “outer cover” as used herein means a structural elementpositioned on the garment-facing surface of the absorbent article. Theouter cover typically forms the chassis onto which other components ofthe diaper are added. The outer cover, however, may just be a coatinglayer on the garment side of the absorbent article.

Suitable material for the outer cover should provide a nonwoven web thatprovides a garment-like fit character to the absorbent article as wellas a structural support for the barrier layer and absorbent core. Theouter cover should not be the rate limiting element to gas or vaportransport through the absorbent article. Preferably, the outer cover hasa structure that is relatively open to allow for convective air or gaspermeability. The suitable outer cover typically has a water vaportransmission rate (WVTR) of at least about 5000 gsm/day, more preferablyof at least about 15,000 gsm/day, and most preferably at least about30,000 gsm/day. Additionally, the outer cover provides a soft, pleasantfeel to the skin, either by the material property, or by texturizing orembossing its surface, or both.

The outer cover may be a single layer of homogeneous or multi-componentmaterial, or a composite of various layers of materials. The outer coversuitable for use herein comprises porous materials such as an aperturedfilm (e.g., having a plurality of shaped openings or angledcapillaries), a knitted web, a porous woven or nonwoven web, a foam, orcombinations or laminates thereof. In one embodiment, the outer covercomprises nonwoven webs or multi-layered nonwovens such as spunbondnonwoven (SB), spunbond/meltblown nonwoven (SB/MB),spunbond/meltblown/spunbond (SBS) nonwoven.

In certain embodiments, the outer cover may include a backsheet that ismade of an apertured, thin plastic film such as a thermoplastic filmhaving a thickness of about 0.012 mm (0.5 mil) to about 0.051 mm (2.0mils). Suitable backsheet films include those manufactured by TredegarCorporation, based in Richmond, Va., and sold under the trade name CPC2film. Other suitable backsheet materials may include breathablematerials which permit vapors to escape from the absorbent article whilestill preventing exudates from passing through the backsheet. Somebreathable composite materials are described in greater detail in U.S.Pat. Nos. 5,938,648, 5,865,823, and 5,571,096.

The outer cover, or any portion thereof, may be elastically extensiblein one or more directions. In one embodiment, the outer cover maycomprise a structural elastic-like film (“SELF”) web. A SELF web is anextensible material that exhibits an elastic-like behavior in thedirection of elongation without the use of added elastic materials andis described in more detail in U.S. Pat. No. 5,518,801. In alternateembodiments, the outer cover may combine elastomeric components (such asfilms, foams, strands, or combinations thereof) with nonwovens orsynthetic films.

In another embodiment, the outer cover may be a nonwoven web constructedto provide the required level of liquid impermeability. For example, anonwoven web of spunbonded or meltblown polymer fibers may be treated,at least partially, with a hydrophobic coating. Exemplary treatmentsusing fluorocarbons are described in U.S. Pat. Nos. 5,876,753,5,888,591, 6,045,877, and U.S. patent application Ser. No. 99/20504.

The absorbent article may comprise an outer cover that is separated fromthe absorbent core at least partially by the barrier layer and ispreferably joined to the barrier layer and/or the absorbent core byattachment means such as those well known in the art.

The outer cover may be secured to the barrier layer, topsheet, absorbentcore, or any other element of the absorbent article by any attachmentmeans known in the art. For example, the attachment means may include auniform continuous layer of adhesive, a patterned layer of adhesive, oran array of separate lines, spirals, or spots of adhesive. One preferredattachment means comprises an open pattern network of filaments ofadhesive as disclosed in U.S. Pat. No. 4,573,986. Other suitableattachment means include several lines of adhesive filaments which areswirled into a spiral pattern, as is illustrated by the apparatus andmethods shown in U.S. Pat. Nos. 3,911,173, 4,785,996, and 4,842,666.Adhesives which have been found to be satisfactory are manufactured byH. B. Fuller Company of St. Paul, Minn. and marketed as HL-1620 andHL-1358-XZP. Alternatively, the attachment means may comprise heatbonds, pressure bonds, ultrasonic bonds, dynamic mechanical bonds, orany other suitable attachment means or combinations of these attachmentmeans as are known in the art.

The outer cover material should not significantly lower the convectiveair permeability of the absorbent article. More importantly, thecombination of the barrier layer and the outer cover (hereinafterreferred to as the “combined structure” or “combination”) provide thedesired balance of properties, including, but not limited to, barrierproperty and convective air permeability.

Barrier Layer

The absorbent articles of the present invention provide an improvedbarrier function against liquid or wetness strikethrough upon impact orcontinued application of pressure, even while maintaining a breathablecharacter. This benefit is brought about by the inclusion of a barrierlayer in the absorbent article. This barrier layer comprises a firstregion upon which a barrier coating is disposed and a second region ontowhich substantially no barrier coating is disposed. The barrier coatinginhibits the flow of a liquid and/or water vapor in the first region ofthe barrier layer as compared to the flow of the liquid in the secondregion of the barrier layer such that the first region of this barrierlayer exhibits a water vapor transmission rate (WVTR) of from about 100to about 50,000 gsm/day and a convective air permeability of at leastabout 0.01 cfm. The barrier layer allows convective air or water vaportransport though the entire composite structure while minimizing theamount of actual liquid that can pass through the partially occluded (orcoated) first region as compared to the second region of its barrierlayer. Particularly, this layer of the presently claimed absorbentarticle and/or composite achieves the desirable convective air flowcapacity without sacrificing the barrier protection against wet through.Thus, a barrier layer inclusive absorbent article shows effectivereduction of the relative humidity in the space between the absorbentarticle and the wearer, thus, improves and/or maintains skin health andwearer comfort.

The barrier coating may be applied to the first region in a variety ofmanners including, but not limited to, dipping, brushing, coating,printing, slot-coating, powder coating, and combinations thereof.Preferably, though the barrier coating is applied via a mechanismselected from the group consisting of dipping, brushing, coating,printing, slot-coating, and combinations thereof.

The coated first region of the present invention may be constructed tohave a convective air permeability of at least about 0.01 cfm,preferably at least about 0.05 cfm, and most preferably at least about0.1 cfm. Convective air permeability is especially effective in removingwater vapor from inside the absorbent article, resulting in a lowerhumidity in the local environment next to the skin, which reducesincidences of skin irritation or rash and promotes skin health. On theother hand, uncoated second region may be constructed to exhibit aconvective air permeability of greater than about 0.1 cfm, preferablygreater than about 1 cfm, and most preferably greater than about 10 cfm.

Moreover, it is important that this coated portion of the barrier layerexhibit a WVTR of from about 100 to about 50,000 gsm/day, morepreferably from about 200 to about 25,000 gsm/day, even more preferablyfrom about 300 to about 15,000 gsm/day, still more preferably from about400 to abut 10,000 gsm/day, and most preferably from about 500 to about5,000 gsm/day.

It has been found that when these features are combined, a disposablecomposite as disclosed herein is quite effective at providing thebenefits deemed desirable when a consumer is looking for a breathableabsorbent article for containment of body exudates, protective wear, oreven personal hygiene care.

In preferred embodiments, the coated first region of the composites andabsorbent articles of the present invention preferably has a dynamicliquid impact value of less than or equal to about 60 gsm, morepreferably of less than or equal to about 40 gsm, even more preferablyof less than or equal to about 20 gsm, and most preferably of less thanor equal to about 7 gsm. In contrast, the second region preferably has adynamic liquid impact value of greater than about 70 gsm.

In other preferred embodiments, the coated first region exhibits abarrier property that is measured by the Hydrohead Pressure Test that isdescribed below. The hydrohead value of the first region that is coatedwith the barrier coating should be higher than that of a second or anyadditional regions of the same component on which no barrier coating ispresent. Preferably, this difference in hydrohead value between thebarrier coated first region and the non-coated second region of the samecomponent is at least about 1 mbar, more preferably at least about 5mbars, and even more preferably at least about 10 mbars. The barriercoating preferably imparts an overall liquid resistance to the absorbentarticle (excluding the absorbent core and any tissue layers) of thepresent invention such that the coated first region of the barrier layerexhibits a hydrohead value of at least about 60 mbar, preferably atleast about 70 mbar, more preferably at least about 80 mbar, and mostpreferably at least about 90 mbar.

The hydrohead value of the coated first region of the barrier layer maybe affected if the barrier layer further comprises a fibrous web.Hydrohead values of such a fibrous web barrier layer would increase withfiner fiber diameter, higher fiber density, higher basis weight, orcombinations thereof. Suitable fibrous web on which the barrier coatingmay be disposed typically has a basis weight of at least about 2 gsm,preferably from about 5 to about 100 gsm, more preferably from about 10to about 75 gsm, and most preferably from about 15 to about 55 gsm.

Without being limited by theory, convective transport capacity isdifferent from diffusive transport capacity. The convective (i.e., bothforced and free) transport is driven by a gas or air pressuredifferential and is typically at a much higher transport rate thandiffusive transport, which is driven by random molecular movements. Atypical example of diffusive transport includes the moisture migrationthrough the pores of a microporous film such as those known in the artas the backsheet materials, or through the molecular structure of anonporous monolithic film such as that made from Hytrel® (available fromDuPont, Wilmington, Del.). Convective transport, on the other hand, isdirected by the air pressure differential between the inside and theoutside of the article. Though the local pressure (i.e., the localpressure within the space between the article and the wearer) and thepressure of the environment (i.e., outside the article) aresubstantially the same, small changes in the local pressure may causeconvective air flow, typically through the gaps between the wearer andthe article. Factors that may lead to convective transport include, butare not limited to, movements by the wearer, small pressure and/ortemperature differential between the local and the outside environment,and the like.

With the advances made to absorbent articles, using elastic materialsand elastic components, the absorbent articles now provide a tighterseal (i.e., fewer gaps) against the wearer's body to minimize fluidleakage to the outside. Consequently, the convective vapor flow throughthe gaps is substantially reduced, leading to a humid and hot localenvironment in the space between the article and the wearer. Whileabsorbent cores are typically air permeable, the air permeabilitytypically is reduced when the cores absorb liquid (i.e., become loaded).This air permeability is significantly affected further when microporousfilm backsheets are included in an article. The loaded cores can bevented (i.e., made air permeable) relatively easily, typically byventing means. Alternatively, openness of the core structures can beachieved by selecting particular arrangements of permeable materials.

These vented or open-structured cores generally require a leakageprotection component, which is typically a microporous film backsheet ora relatively thick nonwoven fabric that provides liquid impermeabilityand leakage protection. These liquid impermeable components, however,tend to drastically reduce the air permeability of the overall absorbentarticle such that the convective air permeability of such components isvirtually undetectable. In contrast, the barrier layer of the presentarticles allows convective air flow through the layer itself and thusthrough the entire article.

Typically, the barrier layer is positioned between the absorbent coreand the outer cover, preferably adjacent to the garment-facing side ofthe absorbent core. In certain embodiments, the barrier layer may evenbe a component of the core, e.g., acting as a dusting layer. The barrierlayer may be of a unitary structure. Alternatively, the layer may be acomposite structure, which comprises a plurality of individual regionsof materials that are joined or operatively associated together. Theindividual regions of the barrier layer may be coextensive ornon-coextensive, depending on the requirements of the absorbent article.The individual regions may be joined by attachment means such as thosewell known in the art.

For example, the regions may be secured together by a uniform continuouslayer of adhesive, or an array of separate lines, spirals, or dropletsor beads of adhesive. The adhesive may be applied continuously orintermittently. For example, each application of the adhesive spans thelength of the barrier layer and is separated from one another by aselected distance. The adhesive is applied to tack the regions togetherfor handling the webs in the assembly process. Preferably, the adhesiveis applied to portions of the surface of the barrier layer, leavingsufficient open (i.e., free of adhesives) surface areas for air/vaporpermeability. Alternatively, the adhesive may be applied to modify theliquid impermeability. Typically, the open or adhesive-free surface areais no less than about 50%, preferably no less than about 70%, morepreferably no less than about 80%, and most preferably no less thanabout 90% of the total surface area of the barrier layer. Suitableadhesives are manufactured by H. B. Fuller Company of St. Paul, Minn.and marketed as HL-1258 and by Ato-Findley Inc. of Milwaukee, Wis.,under the trade designation H2031F.

Alternatively, the attachment means may comprise heat bonds, pressurebonds, ultrasonic bonds, mechanical bonds (via, for example,entanglements, cohesive forces, electric or static charges) or any othersuitable attachment means or combinations of these attachment means asare known in the art.

Though the liquids are mainly absorbed by the absorbent core, thebarrier layer provides additional leakage protection against errantliquids that are not absorbed by or are released from the absorbentcore. Therefore, it is foreseeable that an additional absorbent layermay be included in the absorbent article of the present invention to actas a secondary absorbent or containment means to the core.

Liquid absorbency may vary, depending on the materials used in theabsorbent core, the surface tension of the liquid being tested forabsorbency, and the contact angle between the test liquid and thematerial.

The thickness and basis weight of the barrier layer may vary, dependingon the materials used, the properties desired, the intended use, theconstruction, and the like. For example, thickness and/or basis weightmay affect the diffusive breathability and/or the convective airpermeability between the interior of an article and the outside, theabsorbency and/or leakage protection of the article, the fit of thearticle to the wearer's body, the wearer's comfort, and like effectsthat typically relate to thickness of a structure. Typically, thebarrier layer of the present invention intended for use in an absorbentarticle has a thickness of less than about 1.5 mm, preferably less thanabout 1.2 mm, and more preferably less than about 1.0 mm. The thicknessof the barrier layer suitable for use in an absorbent article shouldalso have a minimal thickness greater than about 0.1 mm, preferablygreater than about 0.2 mm. Suitable materials for use herein aredisclosed in U.S. Pat. Nos. 6,413,344, 6,521,555, and 6,488,801, allassigned to First Quality Nonwovens, Inc. (FQN). In particular, a 20 gsmmeltblown from FQN is preferred for use herein.

The barrier coating and hence the first region is “substantiallyimpermeable” to liquids, including water, breast milk, urine, menses,and other bodily fluids. The term “substantially impermeable” means thatthe barrier coating exhibits a resistance to liquid penetration but doesnot necessarily eliminate liquid wet through. In other words, it ispossible for liquid to penetrate and flow through the barrier coatingunder normal wear conditions, such as under impact force, high appliedpressure, or under sustained (i.e., continuously applied) pressure for aperiod of time. For example, when the first region of the barrier layeris positioned adjacent to the region of the absorbent core that istypically loaded with liquid upon insult, it provides additionalprotection against wet-through, particularly when the liquid loadinglevel is high and/or the loaded absorbent core is under a sudden, highimpact force or a sustained force/pressure.

This added wet-through protection is especially beneficial in diapers,training pants, pull-on diapers, or adult incontinence products, forwhich the liquid loading level can be fairly high (in comparison tofeminine hygiene products) and the probability of sudden impact orsustained pressure (e.g., when babies or incontinent adults fall, sitdown, roll, sleep) is also high. The barrier layer of the presentlyclaimed absorbent articles and composites proves beneficial when theabsorbent core is subjected to gushes of liquids. The resistance toliquid wet through provided by the barrier coating serves to temporarilyslow down the gushes of liquids, possibly pooling the liquids at theinterface between the absorbent core and the barrier coating. The slowedflow and pooling provide the additional time for the absorbent core toacquire and distribute the liquids to other regions of the core beyondthe point of insult. Consequently, the absorbent core may achieve itsfull absorbent capacity.

The function of the barrier layer component of the present invention canbe more clearly understood by referring to the following illustrativefigures. FIG. 2 shows a plan view of a composite of the article of thepresent invention. The barrier layer 10 comprises a first region 14,which coincides with the barrier coating 12 and a second region 16,which is uncoated. As indicated in earlier discussion, the barriercoated first region is typically placed on the barrier layer in the areawhich is most prone to insult by the wearer's bodily exudates (in thecase of a diaper or feminine care product) or in the area which is mostlikely to come in contact with wetness (in the case of other disposablegarments).

Various arrangements of the barrier coating in the barrier layer areshown in FIG. 3. In FIG. 3, the first region 14 is striped inrelationship to the second region within the barrier layer such thatmultiple regions are formed. In FIG. 3, the barrier coating 12 isdisposed in a first region in the form of a discrete stripe shape, whichcould likewise be in alternative shapes or discontinuous patterns, suchas circles, ellipses, squares, animated characters, etc.

In preferred embodiments of the present invention, at least a portion ofthe barrier coating is positioned adjacent to the garment-facing side ofthe absorbent core. In one embodiment, the barrier coating may extendthrough substantially the entire portion of the absorbent core or thebarrier coating may be stripes or patches that extend to portions of theabsorbent core. In another embodiment, the barrier layer may extendbeyond the outer edges of the absorbent core or only through the lengthand width of the central portion of the absorbent core. Configurationsin which the barrier coating has at least the same length and width ofthe absorbent core are highly preferred. An even more preferredembodiment includes a barrier coating on the region of the barrier layerthat is most prone to insult by a wearer (in the case of an absorbentarticle).

Moreover, the barrier coated first region may cover the expanse of atleast about 5% of the entire area of the barrier layer. More preferably,the barrier coating is disposed on at least about 15% of the entirearea. Even more preferably, the barrier coating is disposed on at leastabout 25% of the entire area. Most preferably, however, the barriercoating covers at least about 50% of the entire area of the barrierlayer.

Additionally, irrespective of the amount of area that is covered by thebarrier coating, the coating may be applied in a gradient in the crossdirection, machine direction, or both. Likewise, the pattern formed bythe barrier coating may be continuous or intermittent in form asdiscussed above with the stripes, dots, etc. along the width or lengthof the layer.

In order to provide the desired hydrohead value or the “barrier-like”property, the barrier coating comprises one or more materials thatsubstantially closes or block the openings (as opposed to the fulllength) of the pores of the portion of the barrier layer onto which itis deposited. More specifically, the barrier coating comprises one ormore materials selected from the group consisting of thermoplasticmaterials (such as hotmelt adhesives), solutions, emulsions,dispersions, and combinations thereof. For instance, suitable barriercoating comprises materials selected from the group consisting ofmicrocrystalline waxes, stearyl behenates, sucrose fatty acids,polyisobutylenes, ethylene-vinyl acetate copolymer resins, polyethylenewaxes, fatty alcohols, sucrose fatty acid esters, stearyl alcohol,sucrose hardened soy esters having an iodine value of less than 107(preferably less than 90), natural alcohol still bottoms, wax esters(e.g., sorbitan wax ester, fatty-fatty wax ester, sucrose wax esters),aldol condensation products with melting points greater than 60° C.,natural petroleum waxes, lube base stocks, ozokerite wax, syntheticpetroleum waxes, beeswax, stearic acids, spermaceti, carnauba wax,hydrogenated soybean oil, unhydrogenated soybean oil, corn oil, palmoil, coconut oil, castor oil, linseed oil, safflower oil, sunflower oil,rapeseed oil, silicones, xanthan gum, gum arabic, celluloses, chemicaland enzyme-modified starches, petrolatums, mineral oils, vinylcopolymers, vinyl emulsifiers, sorbitol, propylene glycol, glycerine,solid esters, and combinations thereof. More preferably, the barriercoating comprises one or more materials selected from the groupconsisting of microcrystalline waxes, thermoplastic materials, stearylbehenates, stearyl alcohols, silicones, silicone waxes, and combinationsthereof. Even more preferably, the barrier coating comprises one or morematerials selected from the group consisting of microcrystalline waxes,hotmelt adhesives, and combinations thereof. Suitable hotmelt adhesivesinclude H. B. Fuller's HL-1258.

Most preferred as a barrier coating is a microcrystalline wax. Asuitable wax for use in the present invention is Multiwax W-835, whichis commercially available from The C.P. Hall Company. This material is ahighly refined, high molecular weight microcrystalline petroleum waxthat consists of saturated branched and cyclic non-polar hydrocarbons.

In certain embodiments, it is preferred that such barrier coatingmaterials are disposed onto a first region of the barrier layer suchthat the basis weight of the coated first region ranges from about 5 toabout 200 gsm, more preferably from about 10 to about 100 gsm, even morepreferably from about 15 to about 75 gsm, and most preferably from about25 to about 50 gsm.

It is desirable that the barrier coating wet the barrier layer in thefirst region even when the layer itself is modified with othertreatments (e.g., polypropylene web treated with plasma, a hydrophobicsurface coating, etc.)

Other Components

In order to optimize the absorbent article disclosed herein, it may bedesirable to ensure that it includes one or more of the belowmentionedfeatures.

The absorbent article may also include a fastening system 40. Thefastening system 40 preferably maintains the first waist region 36 andthe second waist region 38 in a configuration so as to provide lateraltensions about the circumference of the absorbent article to hold theabsorbent article on the wearer. The fastening system preferablycomprises a fastener such as tape tabs, hook and loop fasteningcomponents, interlocking fasteners such as tabs & slots, buckles,buttons, snaps, and/or hermaphroditic fastening components, although anyother known fastening means are generally acceptable. Some exemplarysurface fastening systems are disclosed in U.S. Pat. Nos. 3,848,594,4,662,875, 4,846,815, 4,894,060, 4,946,527, 5,151,092, and 5,221,274. Anexemplary interlocking fastening system is disclosed in U.S. Pat. No.6,432,098. The fastening system may also provide a means for holding thearticle in a disposal configuration as disclosed in U.S. Pat. No.4,963,140. The fastening system may also include primary and secondaryfastening systems, as disclosed in U.S. Pat. No. 4,699,622 or to improvefit as disclosed in U.S. Pat. Nos. 5,242,436, 5,499,978, 5,507,736, and5,591,152.

The absorbent article may also comprise side panels. The side panels maybe elastic or extensible to provide a more comfortable and contouringfit by initially conformably fitting the diaper to the wearer andsustaining this fit throughout the time of wear well past when thediaper has been loaded with exudates since the elasticized side panelsallow the sides of the diaper to expand and contract. The side panels 30may also provide more effective application of the diaper because evenif the diaperer pulls one elasticized side panel farther than the otherduring application, the diaper will “self-adjust” during wear.

While the diaper of the present invention preferably has the side panelsdisposed in the second waist region, the diaper may be provided withside panels disposed in the first waist region or in both the firstwaist region and the second waist region. The side panels 30 may beconstructed in any suitable configurations. Examples of diapers withelasticized side panels are disclosed in U.S. Pat. Nos. 4,857,067,4,381,781, 4,938,753, 5,151,092, 5,221,274, 5,669,897, and 6,004,306.

In a preferred embodiment, the absorbent article further comprises atleast a first cuff for providing improved containment of liquids andother body exudates; an elastic waist feature that provides improved fitand containment; and a fastening system which forms a side closure whichmaintains the first waist region and the second waist region in anoverlapping configuration such that lateral tensions are maintainedaround the circumference of the absorbent article to maintain theabsorbent article on the wearer. The absorbent article may also compriseelasticized side panels (not shown) in the waist regions and to providean elastically extensible feature that provides a more comfortable andcontouring fit and more effective application of the absorbent article.

The elasticized leg cuffs 32 can be constructed in a number of differentconfigurations, including those described in U.S. Pat. Nos. 3,860,003,4,636,207, 4,695,278, 4,704,115, 4,795,454, 4,900,317, 4,909,803(Reissued as U.S. RE 34920), 5,085,654, 5,492,751, 6,476,288 and SIRH1630.

For example, the absorbent article may include one ore more first cuffsthat provide improved containment of liquids and other body exudates.First cuffs may also be referred to as outer leg cuff, leg bands, sideflaps, leg cuffs or elastic cuffs. U.S. Pat. No. 3,860,003 describes adisposable diaper which provides a contractible leg opening having aside flap and one or more elastic members to provide an elasticized legcuff.

Additionally, an absorbent article of the present invention may includeone or more second cuffs that also provide improved containment ofliquids and other body exudates. Second cuffs may also be referred to asbarrier leg cuffs, inner leg cuffs or “stand-up” elasticized flaps. U.S.Pat. Nos. 4,808,178 and 4,909,803 describe disposable diapers having“stand-up” elasticized flaps that improve the containment of the legregions.

First cuff and second cuff may both be provided by way of a dual cuff,as exampled in U.S. Pat. Nos. 4,695,278 and 4,795,454. Additional cuffsmay be provided in an article of the present invention as detailed in USStatutory Invention Registration H1630, which published Jan. 7, 1997.

Another component that may be included in the articles or composites ofthe present invention is a hydrophobic surface coating as disclosed incopending U.S. provisional application Ser. No. 60/543,785 (P&G Case9528P). This hydrophobic surface coating may be paired with the barriercoating of the present invention on the barrier layer or may be disposedadjacent to one or more additional components of the absorbent articlesor composites of the present invention. For instance, this hydrophobicsurface coating may be disposed on an interior surface of one or moreleg cuffs, waist portions, or other areas of the absorbent article.

Embodiments of the present invention may also include pockets forreceiving and containing waste, spacers which provide voids for waste,barriers for limiting the movement of waste in the article, compartmentsor voids which accept and contain waste materials deposited in thediaper, and the like, or any combinations thereof. Examples of pocketsand spacers for use in absorbent products are described in U.S. Pat.Nos. 5,514,121, 5,171,236, 5,397,318, 5,540,671, 6,168,584, 5,306,266,5,997,520. Examples of compartments or voids are disclosed in U.S. Pat.Nos. 4,968,312, 4,990,147, 5,062,840, 5,269,755. Examples of suitabletransverse barriers are described in U.S. Pat. No. 5,554,142, PCT PatentWO 94/14395, and U.S. Pat. No. 5,653,703. Examples of other structuresespecially suitable for management of low viscosity feces are disclosedin U.S. Pat. Nos. 5,941,864, 5,977,430, and 6,013,063.

All documents cited in the Detailed Description of the Invention are, inrelevant part, incorporated herein by reference; the citation of anydocument is not to be construed as an admission that it is prior artwith respect to the present invention.

Test Methods

Convective Air Permeability

The convective air permeability is determined by measuring the time inwhich a standard volume of air is drawn through a test specimen at aconstant pressure and temperature. This test is particularly suited tomaterials having relatively high permeability to gases, such asnonwovens, apertured films and the like.

A TexTest FX3300 air permeability tester is used. The test methodconforms to ASTM D737. The test is operated in a laboratory environmenttypically about 23±2° C. and about 30%±15% relative humidity. The testspecimen has to be conditioned for at least 2 hrs. The test pressure is125 Pascals and the test area is 38 cm². In this test, the instrumentcreates a constant differential pressure across the sample which drawsair through the sample. The rate of air flow through the sample ismeasured in cfm. For each sample, five replicates should be run, and theaveraged result is reported as the air permeability value.

Hydrostatic Head (Hydrohead) Pressure Test

The hydrohead pressure or hydrohead value is a measure of the liquidbarrier property (or liquid impermeability) of a material. Specifically,the test described herein measures the hydrostatic pressure the materialwill support when water penetration occurs.

The TexTest Hydrostatic Head Tester FX3000 (available from AdvancedTesting Instruments, Corp., Spartanburg, S.C.) is used. The test methodconforms to Edana 120.1-18 (also INDA IST 80.6). For this test,gradually increasing pressure is applied to a defined sample portionuntil water penetrates through the sample.

The test is conducted in a laboratory environment typically about 73°F.±2.0° F. (23° C.±2° C.) and a relative humidity of about 30±15%. Thesample is clamped over the top of the column fixture, using anappropriate gasketing material (o-ring style) to prevent side leakageduring testing. In order to determine the hydrohead pressure of thebarrier coated first region of the barrier layer, a sample of thebarrier layer is oriented such that the barrier coated region of thebarrier layer faces the water column during the test. The area of watercontact with the sample is equal to the cross sectional area of thewater column, which equals 28 cm² or 100 cm². Similarly, the hydroheadpressure of the uncoated second region is determined by orienting thisregion facing the water column during the test.

In either instance, water is pumped into the water column at a rate toachieve a pressure increase of 3 mbar/min or 60 mbar/min. Thus, thesample is subjected to a steadily increasing water pressure on onesurface. When water penetration appears on three locations on the othersurface of the sample, the pressure at which the third penetrationoccurs is recorded. If water immediately penetrates the sample (i.e.,the sample provided no resistance), a zero reading is recorded. For eachmaterial, five specimens are tested and the results are averaged andreported in mbars.

Dynamic Liquid Impact Value

The objective of the test method is to mimic the dynamic load/area(energy) that a baby will impart to a saturated core/backsheet structurewhen the baby abruptly goes from a standing to a sitting position.Dynamic liquid impact (g/m²) is calculated based on the impact energy anaverage 20 lb. baby will impart to a saturated diaper if he/she “falls”onto it from a standing position. The baby was modeled as two rigidlinks of known mass and length. The theory was made that the links“fall” from rest, with the impact area being the region under thediaper. This works out to be approximately 20 Joules (14.75 ft-lb.) overan average baby “seat” area 0.0087 m² (˜13.5 in²) or 2300 J/m². In orderto conduct this method, a dynamic liquid impact tester is required. Thistester is depicted in FIG. 4.

Test Equipment and Supplies

-   -   1. Bottom plate 214 (305 mm×305 mm steel plate, 25.5 mm thick);    -   2. Impact disc 212 (white nylon (McMaster Carr #8538K34) 61 mm        dia., 12.7 mm thick) with a 5 mm pin 220 inserted in the        center);    -   3. Lexan sample plate 206 (153 mm×153 mm Lexan plastic block, 19        mm thick, which includes a circular cut out area for insertion        of the guide tube 204;    -   4. Lexan guide tube 204 (Lexan plastic tube of 3 mm thickness        and an inner diameter of 64 mm;    -   5. Impact weight 209 (3370 g+5 g stainless steel cylinder, 149        mm long and a diameter that is lightly less than that of the        guide tube 204 to allow it to move freely in the vertical        direction therein);    -   6. Vacuum cup 208;    -   7. Impact pad 222 (Silicon Rubber Sheet, 50 A durometer        hardness, 6″×6″×⅜″ thick;    -   8. Filter paper (Whatman #4 Filter Paper, 1004-070, 70 mm        diameter, VWR catalog # 28460-041);    -   9. Liquid used to load filter paper (0.9% Sodium Chloride        solution);    -   10. 10 ml plastic syringe or equivalent;    -   11. Starrett rules (Starrett 150 mm Rule, Starrett 300 mm Rule);        and    -   12. Control material (125 mm×125 mm Exxaire Exxon XBF 100W).        Parts 1-7 are assembled as shown in FIG. 4. The distance between        the bottom of the impact weight 209 to the bottom of the impact        pad 212 is set to 40 mm±3.0 mm.

It is important to note that this method uses two filter papers torecord the moisture transferred through the test sample. It alsorequires a stack of five filter papers to carry the wetting medium.

The two “receiving” filter papers are weighed to within ±0.1 mg and themass is recorded. The stack of five filter papers need only be weighedto within ±0.01 g.

Test Steps

-   1. Place two pieces of 70 mm diameter filter paper on a balance    accurate to 0.0001 gram. Record the filter paper's mass after about    one minute or when balance reading stabilizes.-   2. Place five pieces of 70 mm diameter filter paper onto a balance    accurate to 0.01 gram. Assure a “dry” mass is 1.72 g+0.10 g.-   3. Raise the bottommost portion of the impact weight to a height of    290 mm+2 mm from the top of the base plate.-   4. Remove the Lexan sample plate and center the five filter papers    on the impact pad, which is centered on the base plate.-   5. Set two timers: set one for 2 minutes and set the other for 3    minutes. The 2-minute timer signals when to raise the impact weight.    The 3-minute timer signals when to record the final weight of the    two filter papers.-   6. Draw 2.0 ml (+0.05 ml) of 0.9% NaCl solution into a calibrated    syringe. Apply the NaCl solution to the five filter papers.-   7. Place a 125 mm×125 mm section of test material on the saturated    filter papers assuring the wet filter papers remain in the “stacked”    position. The side of the material that would be the outside of the    absorbent article needs to face up. (Note—The time between placing    the test material on the wet filter papers and releasing the impact    weight must be minimized. Assure all activities, i.e., setting    timers, weighing the filter paper, are completed)-   8. Place the Lexan sample plate over the test material while    insuring that the aperture contained therein is aligned with the    bottom of impact weight.-   9. Using tweezers/tongs place the two receiving, weighed filter    papers over the test material.-   10. Release the impact weight and start both timers.-   11. When the 2-minute timer signals, raise the impact weight and    secure it.-   12. Promptly transfer the two filter papers (using tweezers/tongs)    to the balance valid to 0.0001 g.-   13. When the 3-minute timer signals, record the filter paper's mass    to the nearest 0.0001 g.-   14. Remove the Lexan sample plate, the test material and wet filter    paper from the LIT. Dry the rubber pad and the Lexan sample plate    with a Bounty towel (or equivalent). Repeat steps 1-2 and 5-14 for    next test.    Calculation of Dynamic Liquid Impact Value    “Dynamic” Liquid Impact Value=Filter Mass Change(grams)/Impact    Area(m²)Impact Area=0.002932 m²    Sample Calculation:

Filter Filter Filter Mass Dynamic Dry Mass Wet Mass Change Impact Value(grams) (grams) (grams) (g/m²) 0.3465 0.3815 0.0350 11.9

-   -   0.0350 g/0.002932 m²=11.9372 g/m² (or gsm)        Water Vapor Transmission Rate

The water vapor transmission rate is a measure of the rate at whichwater vapor flows through flexible barrier materials. Accordingly, INDAIST 70.4(01), which is the Standard Test Method for Water VaporTransmission Rates of 500 to 100,000 gsm/day Through Nonwoven Fabricsand Plastic Barriers, is used to determine the WVTR of the entireabsorbent article's thickness.

EXAMPLES Example 1

A composite according to the present invention is prepared.

A microcrystalline wax barrier coating (commercially available from TheC. P. Hall Company under the tradename Witco W-835) is applied to a 20gsm meltblown from First Quality Nonwovens, Inc. which measures 142mm×132 mm using a Nordson hotmelt slot coater at an add-on rate of 33gsm. This coating extends across the width of the layer covering about25% of area of the barrier layer.

Example 2

A composite according to the present invention is prepared.

The composite of Example 1 is modified to further include a hydrophobicsurface coating that is added to the meltblown prior to the addition ofthe wax barrier coating. This hydrophobic surface coating is an aqueousmixture of vinyl terminated polydimethyl siloxane and methylhydrogenpolydimethyl siloxane in a 30:1 ratio in order that approximately 0.1gsm of the aqueous silicone mixture (which includes a transition metalcatalyst) is deposited via a kiss roll onto the meltblown in at leastthe first region. The meltblown barrier layer is dried at 120° C. for1-3 minutes. Thereafter, the barrier coating of Example 1 is applied asdetailed above.

Example 3

An absorbent article according to the present invention is prepared.

A multi-piece diaper is constructed with a barrier layer with a barriercoating that is longer and wider than the absorbent core, extending upto the gasketing leg cuff portion and 10 mm beyond each end of theabsorbent core. The composite of Example 1 or 2 is placed between theabsorbent core and the outer cover with the barrier coating facing thecore in a diaper as detailed in any one of U.S. Pat. Nos. 3,860,003,4,636,207, 4,695,278, 4,704,115, 4,795,454, 4,900,317, 4,909,803(Reissued as U.S. RE 34920), 5,085,654, 5,492,751, 6,476,288, 6,627,787,5,507,760, 5,609,587, 5,635,191, 5,643,588, 6,118,041 and SIR H1630.

Example 4

An absorbent article of the present invention is prepared.

The composite of Example 1 or 2 is modified to include a 22 gsmInterlake tissue (absorbent layer) on the surface facing the outer coverof a diaper prepared as detailed in Example 3.

Example 5

A pull-on type absorbent article of the present invention is prepared.

A pull-on type absorbent article as detailed in any one of U.S. Pat.Nos. 5,246,433, 5,769,838, 5,899,895, 5,899,896, and 6,120,487 ismodified to include the composite of Example 1 or 2.

Example 6

A pull-on type absorbent article of the present invention is prepared.

The composite of Example 1 or 2 is modified to include a 22 gsmInterlake tissue (absorbent layer) on the surface of the composite whichis placed facing the outer cover of the pull-on article of Example 5.

All documents cited in the Detailed Description of the Invention are, inrelevant part, incorporated herein by reference; the citation of anydocument is not to be construed as an admission that it is prior artwith respect to the present invention.

While particular embodiments of the present invention have beenillustrated and described, it would be obvious to those skilled in theart that various other changes and modifications can be made withoutdeparting from the spirit and scope of the invention. It is thereforeintended to cover in the appended claims all such changes andmodifications that are within the scope of this invention.

1. A disposable absorbent article comprising: a. a liquid permeabletopsheet; b. a liquid impervious outer cover; c. an absorbent coredisposed between said topsheet and outer cover; and d. a barrier layercomprising a fibrous sheet having a first side and an opposing secondside, said first side having a total surface area, the barrier layerbeing disposed between said core and outer cover, wherein said barrierlayer further comprises: 1) a first region of the fibrous sheet having afirst region surface area on said first side, the first region surfacearea forming a portion of the total surface area, wherein the firstregion surface area is smaller than the total surface area, the firstregion having a non-fibrous coating deposited thereon, the coating beingdisposed on the fibrous sheet between the absorbent core and the outercover: and 2) a second region of the fibrous sheet adjacent said firstregion of the fibrous sheet, having a second region surface area on saidfirst side, the second region surface area forming a portion of thetotal surface area, wherein the second region surface area is smallerthan the total surface area; wherein the non-fibrous coating comprisesone or more materials selected from the group consisting ofmicrocrystalline waxes, stearyl behanates, sucrose fatty acids,polyethylene waxes, fatty alcohols, sucrose fatty esters, stearylalcohol, sucrose hardened soy esters having an iodine value of less than107, natural alcohol still bottoms, wax esters, aldol condensationproducts with melting points greater than 60° C., natural petrolatumwaxes, ozokerite wax, synthetic petroleum waxes, beeswax, stearic acids,carnauba wax, hydrogenated soybean oil, unhydrogenated soybean oil, cornoil, palm oil, coconut oil, castor oil, linseed oil, safflower oil,sunflower oil, rapeseed oil, silicones, silicone waxes, xantham gum, gumarabic, petrolatums, mineral oils, vinyl copolymers, vinyl emulsifiers,sorbitol, propylene glycol, glycerine solid esters and combinationsthereof; wherein the non-fibrous coating inhibits the flow of a liquidin the first region of the fibrous sheet as compared to the flow of theliquid in the second region of the fibrous sheet; wherein said firstregion of the fibrous sheet with the non-fibrous coating exhibits awater vapor transmission rate (WVTR) of from about 100 to about 50,000gsm/day and a convective air permeability of at least about 0.01 cfm;wherein said second region of the fibrous sheet is substantially free ofthe non-fibrous coating and exhibits a convective air permeability of atleast about 0.1 cfm; and wherein the non-fibrous coating is depositedonto the first region of the fibrous sheet via a mechanism selected fromthe group consisting of spraying, dipping, brushing, coating, printing,slot-coating, and combinations thereof.
 2. The article of claim 1wherein said barrier layer further comprises an absorbent layer.
 3. Thearticle of claim 1 wherein the hydrohead value difference between thefirst region of the fibrous sheet and the second region of the fibroussheet is greater than about 1 mbar.
 4. The article of claim 1 whereinsaid first region of the fibrous sheet exhibits a dynamic liquid impactvalue of less than or equal to about 60 gsm.
 5. The article of claim 2wherein said first region of the fibrous sheet exhibits a dynamic liquidimpact value of less than or equal to about 60 gsm.
 6. The article ofclaim 1 wherein said barrier layer is disposed adjacent to one or moreof the topsheet, core, and outer cover.
 7. The article of claim 1wherein said article further comprises an additional component that iscontacted with a hydrophobic surface coating.
 8. The article of claim 1wherein said barrier layer comprises a nonwoven substrate having a basisweight of less than about 45 gsm.
 9. A disposable composite comprising atopsheet, an outer cover, an absorbent core disposed between thetopsheet and the outer cover, and at least one barrier layer disposedbetween the absorbent core and the outer cover, the barrier layercomprising a fibrous sheet having a first side and an opposing secondside, said first side having a total surface area, and furthercomprising: a. a first region of the fibrous sheet having a first regionsurface area on said first side, the first region surface area forming aportion of the total surface area, wherein the first region surface areais smaller than the total surface area, the first region having anon-fibrous coating deposited thereon, the coating being disposed on thefibrous sheet between the absorbent core and the outer cover; and b. asecond region of the fibrous sheet, having a second region surface areaon said first side, the second region surface area forming a portion ofthe total surface area, wherein the second region surface area issmaller than the total surface area; wherein the non-fibrous coatingcomprises one or more materials selected from the group consisting ofmicrocrystalline waxes, stearyl behanates, sucrose fatty acids,polyethylene waxes, fatty alcohols, sucrose fatty esters, stearylalcohol, sucrose hardened soy esters having an iodine value of less than107, natural alcohol still bottoms, wax esters, aldol condensationproducts with melting points greater than 60° C., natural petrolatumwaxes, ozokerite wax, synthetic petroleum waxes, beeswax, stearic acids,carnauba wax, hydrogenated soybean oil, unhydrogenated soybean oil, cornoil, palm oil, coconut oil, castor oil, linseed oil, safflower oil,sunflower oil, rapeseed oil, silicones, silicone waxes, xantham gum, gumarabic, petrolatums, mineral oils, vinyl copolymers, vinyl emulsifiers,sorbitol, propylene glycol, glycerine solid esters and combinationsthereof; wherein the non-fibrous coating inhibits the flow of a liquidin the first region of the fibrous sheet as compared to the flow of theliquid in the second region of the fibrous sheet; wherein said firstregion of the fibrous sheet exhibits a water vapor transmission rate(WVTR) of from about 100 to about 50,000 gsm/day and a convective airpermeability of at least about 0.01 cfm; wherein said second region ofthe fibrous sheet is substantially free of the non-fibrous coating andexhibits a convective air permeability of at least about 0.1 cfm; andwherein the non-fibrous coating is deposited onto the first regionsurface via a mechanism selected from the group consisting of spraying,dipping, brushing, coating, printing, slot-coating, and combinationsthereof.
 10. The composite of claim 9 wherein said barrier layercomprises a nonwoven substrate having a basis weight of less than about45 gsm.
 11. The composite of claim 9 wherein said composite comprises anabsorbent layer.
 12. The composite of claim 9 wherein the hydroheadvalue difference between the first region of the fibrous sheet and thesecond region of the fibrous sheet is greater than about 1 mbar.
 13. Thecomposite of claim 9 wherein said first region of the fibrous sheetexhibits a dynamic liquid impact value of less than or equal to about 60gsm.
 14. The composite of claim 11 wherein said first region of thefibrous sheet exhibits a dynamic liquid impact value of less than orequal to about 60 gsm.
 15. A disposable absorbent article wherein saidarticle comprises the composite of claim
 9. 16. The article of claim 15wherein said article is selected from the group consisting of diapers,training pants, adult incontinence products, feminine care napkins,bibs, care mats, breast pads, wound dressing products, and combinationsthereof.
 17. A disposable absorbent article comprising: a. a liquidpermeable topsheet; b. a liquid impervious outer cover; c. an absorbentcore disposed between said topsheet and outer cover; and d. a barrierlayer comprising a fibrous sheet having a first side and an opposingsecond side, said first side having a total surface area, the barrierlayer being disposed between said core and outer cover, wherein saidbarrier layer further comprises: 1) a first region of the fibrous sheethaving a first region surface area on said first side, the first regionsurface area forming a portion of the total surface area, wherein thefirst region surface area is smaller than the total surface area, thefirst region having a non-fibrous coating comprising a wax depositedthereon, the coating being disposed on the fibrous sheet between theabsorbent core and the outer cover; and 2) a second region of thefibrous sheet adjacent said first region of the fibrous sheet, having asecond region surface area on said first side, the second region surfacearea forming a portion of the total surface area, wherein the secondregion surface area is smaller than the total surface area; wherein thenon-fibrous coating inhibits the flow of a liquid in the first region ofthe fibrous sheet as compared to the flow of the liquid in the secondregion of the fibrous sheet; wherein said first region of the fibroussheet with the non-fibrous coating exhibits a water vapor transmissionrate (WVTR) of from about 100 to about 50,000 gsm/day and a convectiveair permeability of at least about 0.01 cfm; wherein said second regionof the fibrous sheet is substantially free of the non-fibrous coatingand exhibits a convective air permeability of at least about 0.1 cfm;and wherein the non-fibrous coating is deposited onto the first regionof the fibrous sheet via a mechanism selected from the group consistingof spraying, dipping, brushing, coating, printing, slot-coating, andcombinations thereof.